This is probably too much of a hassle to implement. It would mean that you'd have to have a separate class of account (with this one instance for now) where the password may not be changed, past posts may not be edited or deleted, preferences are restricted, the account cannot be deleted, etc. If it were a normal account, trolls would render it unusable immediately.

An alternative is to just allow commenting without being logged in or anonymously while logged in, but I assume they have specific reasons for setting things up the way they did.

It would be nice to be able to post things from time to time without having to worry about it being an unpopular viewpoint that the agree/disagree-bots will vote down as much as they can. I like the slashdot system, where anonymous posting is allowed, with anonymous posts starting with a lower moderation value, and users being able to assign a positive or negative karma modifier for anonymous posts.